Cats can catch and transmit SARS-CoV-2. Credit: Vachira Vachira / NurPhoto / Getty
First there were sneezing hamsters, now sneezing cats. A Thai team reports the first solid evidence of a pet cat infecting a person with SARS-CoV-2, adding cats to the list of animals that can transmit the virus to people.
Researchers say the results are compelling. They are surprised that it has taken so long to establish that transmission can occur, given the scale of the pandemic, the ability of the virus to jump between animal species and close contact between cats and people. “We know this was a possibility for two years,” says Angela Bosco-Lauth, an infectious disease researcher at Colorado State University in Fort Collins.
Early studies of the pandemic found that cats release infectious virus particles and can infect other cats. And throughout the pandemic, countries have reported SARS-CoV-2 infections in dozens of pet cats. But setting the direction of viral spread (from cat to person or from person to cat) is tricky. The Thai study “is an interesting case report and a great example of what good contact tracking can do,” says Marion Koopmans, a virologist at Erasmus University Medical Center in Rotterdam, the Netherlands.
The feline finding, published in Emerging infectious diseases1 on June 6, arose by accident, says co-author Sarunyou Chusri, an infectious disease researcher and doctor at Prince of Songkla University in Hat Yai, southern Thailand. In August, a father and son who had tested positive for SARS-CoV-2 were taken to an isolation room at the university hospital. Her ten-year-old cat was also cleaned and tested positive. As they rubbed him, the cat sneezed into the face of a veterinarian, who was wearing a mask and gloves but no eye protection.
Three days later, the vet had a fever, inhales and cough, and then tested positive for SARS-CoV-2, but none of his close contacts developed COVID-19, suggesting he had been infected by the cat. . Genetic analysis also confirmed that the veterinarian was infected with the same variant as the cat and its owners, and the viral genomic sequences were identical.
Low risk
Researchers say these cases of cat-to-human transmission are likely to be rare. Experimental studies have shown that infected cats do not transmit many viruses, and are only counted for a few days, says Leo Poon, a virologist at the University of Hong Kong.
Still, Chusri says it’s worth taking extra precautions when handling cats suspected of being infected. People “shouldn’t abandon their cats, but take more care of them,” he says.
Other animals suspected of infecting people include farm mink in Europe and North America, pet hamsters in Hong Kong and wild white-tailed deer in Canada. Adding cats to the list “broadens our understanding of the zoonotic potential of this virus,” says Poon.
But researchers say all of these are rare events and animals still don’t play a major role in the spread of the virus. “Humans are still clearly the main source of the virus,” Bosco-Lauth says.